[xml/sgml-pkgs] Bug#732294: what "but please" really requires?

[Samuel Thibault]

Hello,

We would like to include a file in the jing-trang package, the licensing
terms can be read on http://www.ascc.net/xml/schematron/ :

“The Schematron software and this page are available for any public
use, under the conditions of the zlib/libpng license (the least
restrictive), but please mention our names in any documentation or About
screens for any products that uses it.”

What "but please" actually requires?  I would tend to understand that
it's just a wish from the author, not a licensing term, but IANAL.

Samuel